linux-kernel - [tip:timers/core] tick: broadcast-hrtimer: Remove overly clever return value abuse

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Message-ID: <tip-b8a62f1ff0ccb18fdc25c6150d1cd394610f4753@git.kernel.org>
Date:	Wed, 22 Apr 2015 12:13:50 -0700
From:	tip-bot for Thomas Gleixner <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	hpa@...or.com, linux-kernel@...r.kernel.org, peterz@...radead.org,
	preeti@...ux.vnet.ibm.com, mingo@...nel.org, fweisbec@...il.com,
	tglx@...utronix.de, mtosatti@...hat.com, viresh.kumar@...aro.org
Subject: [tip:timers/core] tick: broadcast-hrtimer:
  Remove overly clever return value abuse

Commit-ID:  b8a62f1ff0ccb18fdc25c6150d1cd394610f4753
Gitweb:     http://git.kernel.org/tip/b8a62f1ff0ccb18fdc25c6150d1cd394610f4753
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Tue, 14 Apr 2015 21:09:22 +0000
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Wed, 22 Apr 2015 17:06:52 +0200

tick: broadcast-hrtimer: Remove overly clever return value abuse

The assignment of bc_moved in the conditional construct relies on the
fact that in the case of hrtimer_start() invocation the return value
is always 0. It took me a while to understand it.

We want to get rid of the hrtimer_start() return value. Open code the
logic which makes it readable as well.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Preeti U Murthy <preeti@...ux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@...radead.org>
Cc: Viresh Kumar <viresh.kumar@...aro.org>
Cc: Marcelo Tosatti <mtosatti@...hat.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Link: http://lkml.kernel.org/r/20150414203503.404751457@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 kernel/time/tick-broadcast-hrtimer.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/time/tick-broadcast-hrtimer.c b/kernel/time/tick-broadcast-hrtimer.c
index 6aac4be..96428d7 100644
--- a/kernel/time/tick-broadcast-hrtimer.c
+++ b/kernel/time/tick-broadcast-hrtimer.c
@@ -66,9 +66,11 @@ static int bc_set_next(ktime_t expires, struct clock_event_device *bc)
 	 * hrtimer_{start/cancel} functions call into tracing,
 	 * calls to these functions must be bound within RCU_NONIDLE.
 	 */
-	RCU_NONIDLE(bc_moved = (hrtimer_try_to_cancel(&bctimer) >= 0) ?
-		!hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED) :
-			0);
+	RCU_NONIDLE({
+			bc_moved = hrtimer_try_to_cancel(&bctimer) >= 0;
+			if (bc_moved)
+				hrtimer_start(&bctimer, expires,
+					      HRTIMER_MODE_ABS_PINNED);});
 	if (bc_moved) {
 		/* Bind the "device" to the cpu */
 		bc->bound_on = smp_processor_id();
--
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